I think been are going off the topic in this thread. My initial question was
Can some one let me know will the disk space requirement remain same for same set of tables with same number of rows in postgres 10.x and postgres 9.5.4 ?
You will create a new data directory for 10 and the data from 9.5 will get moved to that new folder after the upgrade. The metadata info in the catalog will get updated accordingly to pg10.
At the end of the upgrade, the 9.5 folder can be dropped after making sure everything is working. This script is also get generated by pg_upgrade.
On moving from postgres 9.5.4 to postgres 10.x we have to do data migration.
Can some one let me know will the disk space requirement remain same for same set of tables with same number of rows in postgres 10.x and postgres 9.5.4 ?